Will McEwan staggers into a church and takes his own life at the altar, leaving behind a suicide note cloaked in religious symbolism — "On the road from Gethsemane to Calvary, I lost my way" — and a pamphlet for a shadowy spiritual group "The Garden." What would lead a young and faithful man to such desperation? Lewis and Hathaway launch an investigation, seemingly aided by the fact that Hathaway knew the victim. But as those most intimately associated with "The Garden" begin to die, Lewis questions Hathaway's sudden vow of silence. In a case involving blind faith and faltering trust, Lewis hurries to know more about the lofty world of Oxford religion and his partner before fire threatens to engulf one final victim.